Smalltalk is another language that has had this feature since forever. Tagged pointers / SmallInteger encodings make the memory overhead zero to negligible, an

Smalltalk is another language that has had this feature since forever. Tagged pointers / SmallInteger encodings make the memory overhead zero to negligible, and with the CPU / memory-bandwidth gap being what it is, the few extra CPU operations rarely matter. Daniel Bernstein made the argument that integers should default to these semantics for security reasons: https://css.csail.mit.edu/6.858/2018/readings/qmail.pdf https://css.csail.mit.edu/6.858/2018/readings/qmail.pdf